Airport month record
MDWSEP
Chicago Midway International in September 2025
- Departures
- 6,459
- Month
- September 2025
- National, same month
- 83.4%
- Carriers
- 4
Historical statistics for September 2025, not live status or a forecast for this year’s September. For today’s conditions at MDW, see live FAA status.
MDW in September earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it level with the national rate of 83.4%. When something does go wrong the average delay runs roughly 45 minutes. That rests on 6,459 flights, with a median arrival 6 minutes early.
Key figures
On time
84.1%
Arrivals under 15 minutes late, of 6,440 completed departures
Avg delay
46 min
Across delayed arrivals only, not all flights
Cancelled
0.06%
Nationally in September: 0.51%
Whole year
75.1%
MDW across all twelve months
These figures cover 6,459 departures from Chicago Midway International in September 2025. On time means an arrival less than 15 minutes after the scheduled gate time, the DOT's threshold, and the national comparison uses every US departure in the same month rather than the whole year.
Against the year
September next to MDW's other months
Against MDW's own year, September ran 9 points better than the twelve-month rate of 75.1%, which makes it the best of the twelve months in the data. Cancellations were unusually low for MDW in September, at 0.06% against 1.49% across the year. Either side of it, August ran 77.8% on time and October 80.2%, so a trip moved by a few weeks would have landed in a worse stretch.
| Month | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| July 2025 | 7,531 | 67.2% | 69 min | 1.81% | C |
| August 2025 | 6,731 | 77.8% | 58 min | 0.74% | B+ |
| September 2025 (this page) | 6,459 | 84.1% | 46 min | 0.06% | B+ |
| October 2025 | 6,536 | 80.2% | 45 min | 0.17% | B+ |
| November 2025 | 5,620 | 80.6% | 59 min | 4.96% | B− |
| December 2025 | 5,738 | 69.7% | 57 min | 0.45% | C+ |
| January 2026 | 4,848 | 80.9% | 50 min | 2.15% | B |
| February 2026 | 4,537 | 81.6% | 46 min | 0.90% | B+ |
| March 2026 | 6,508 | 68.7% | 67 min | 3.89% | C− |
| April 2026 | 6,282 | 77.6% | 52 min | 1.18% | B |
| May 2026 | 6,269 | 74.0% | 53 min | 0.35% | C+ |
| June 2026 | 6,937 | 64.2% | 60 min | 1.53% | D |
Departure window
The best time of day to leave MDW in September
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 15 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am683 flights93.1%
- 8am–11am1,670 flights87.5%
- 11am–2pm1,089 flights85.1%
- 2pm–5pm1,019 flights81.9%
- 5pm–8pm1,179 flights78.5%
- 8pm–5am819 flights78.8%
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.1% of the time, against 78.5% for the evening window. That is 15 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 1,670 flights scheduled in it.
Across the week, Wednesday is the strongest day at 89.7% on time and Thursday the weakest at 79.5%. 10 points is a smaller lever than departure hour, but it is free.
Carrier by carrier
Which airlines ran best at MDW in September
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Southwest Airlines | 6,007 | 83.8% | 45 min | 0.07% | B+ |
| Frontier Airlinesthin sample | 174 | 84.5% | 68 min | 0.00% | B+ |
| SkyWest Airlinesthin sample | 151 | 88.7% | 71 min | 0.00% | A+ |
| Delta Air Linesthin sample | 107 | 93.5% | 49 min | 0.00% | A+ |
Route by route
Busiest routes out of MDW in September
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| MDW to ATL · Atlantathin sample | 292 | 87.7% | 48 min | 0.00% | A+ |
| MDW to MSP · Minneapolisthin sample | 232 | 80.6% | 46 min | 0.00% | B+ |
| MDW to LAS · Las Vegasthin sample | 213 | 83.3% | 42 min | 0.00% | B+ |
| MDW to MCO · Orlandothin sample | 213 | 86.8% | 44 min | 0.00% | A+ |
| MDW to PHX · Phoenixthin sample | 205 | 90.5% | 48 min | 0.98% | A+ |
| MDW to DEN · Denverthin sample | 202 | 85.1% | 55 min | 0.00% | A+ |
| MDW to LGA · New Yorkthin sample | 198 | 79.9% | 40 min | 1.01% | B |
| MDW to DAL · Dallasthin sample | 190 | 80.3% | 48 min | 0.00% | B+ |
| MDW to BWI · Baltimorethin sample | 180 | 85.6% | 59 min | 0.00% | A+ |
| MDW to MCI · Kansas Citythin sample | 177 | 85.3% | 41 min | 0.00% | A+ |
| MDW to DCA · Washingtonthin sample | 176 | 78.4% | 44 min | 0.00% | B+ |
| MDW to HOU · Houstonthin sample | 161 | 89.4% | 42 min | 0.00% | A+ |
| MDW to PHL · Philadelphiathin sample | 159 | 82.4% | 47 min | 0.00% | B+ |
| MDW to BNA · Nashvillethin sample | 159 | 91.8% | 50 min | 0.00% | A+ |
| MDW to STL · St. Louisthin sample | 151 | 92.7% | 36 min | 0.00% | A+ |
| MDW to DTW · Detroitthin sample | 150 | 87.3% | 56 min | 0.00% | A+ |
| MDW to BOS · Bostonthin sample | 128 | 55.5% | 78 min | 0.00% | D+ |
| MDW to OMA · Omahathin sample | 119 | 87.4% | 48 min | 0.00% | A+ |
| MDW to LAX · Los Angelesthin sample | 116 | 75.9% | 46 min | 0.00% | B+ |
| MDW to CMH · Columbusthin sample | 116 | 91.4% | 47 min | 0.00% | A+ |
| MDW to PIT · Pittsburghthin sample | 112 | 87.5% | 39 min | 0.00% | A+ |
| MDW to TPA · Tampathin sample | 111 | 87.4% | 32 min | 0.00% | A+ |
| MDW to CLE · Clevelandthin sample | 108 | 93.5% | 62 min | 0.00% | A+ |
| MDW to AUS · Austinthin sample | 104 | 85.6% | 49 min | 0.00% | A+ |
| MDW to RDU · Raleighthin sample | 90 | 90.0% | 42 min | 0.00% | A+ |
Delay causes
What held MDW up in September
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 47,000 reported delay minutes.
- 37%Carrier
- 34%Late-arriving aircraft
- 26%National Airspace System
- 3%Extreme weather
- 1%Security
34% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 47,000 reported delay minutes here, that single category outweighs weather by 13 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 47,311 reported delay minutes.
Cancellations are rare at 0.06%, below the national 0.51% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Badly late arrivals are rare here: only 3.6% land an hour or more behind schedule, against 5.4% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
What to do with this
Flying from MDW in September
For a September trip through MDW: this is one of the better months to be flying from here, 84.1% on time with 0.06% cancelled. That is a base rate for the month as a whole; a single storm can still spoil a particular day.
Related
Where to go next
- Chicago Midway International (MDW), the whole year
- MDW in July67.2%
- MDW in August77.8%
- MDW in October80.2%
- MDW in November80.6%
- MDW in December69.7%
- MDW in January80.9%
- MDW in February81.6%
- MDW in March68.7%
- MDW in April77.6%
- MDW in May74.0%
- MDW in June64.2%
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.